A pipeline pump unit and a design method of a water compression chamber and a flow channel thereof

Abstract

The application discloses a pipeline pump unit, a water pressure chamber thereof and a flow channel design method thereof, and belongs to the pump unit field. The flow channel design of the application enlarges the base circle design and the spiral water pressure chamber inlet width on the basis of the traditional design, expands the gap between the impeller and the water pressure chamber, and thus can effectively reduce the strength of the dynamic and static interference between the impeller and the water pressure chamber during the pump operation, reduce the pressure pulsation generated at the outlet side of the impeller blade due to the dynamic and static interference during the pump operation, and thus reduce the flow-induced noise and flow loss. Meanwhile, the gap between the impeller and the water pressure chamber is expanded, the allowable error is increased, the interference problem between the flow channels of the impeller and the water pressure chamber caused by the machining and manufacturing errors can be avoided, and the impeller with different widths and radii corresponding to different flow requirements can be compatible under the premise of meeting the performance, so that the product platform is realized and the universality of the product is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pump unit flow passage design, more particularly to a pipeline pump unit, a water plenum thereof and a flow passage design method thereof. BACKGROUND

[0002] In the field of pump units, spiral water plenums are widely used in various types of pumps, such as centrifugal pumps and mixed flow pumps, due to their ideal flow, strong adaptability, and wide high-efficiency range. As a core hydraulic component, the rationality of the flow passage structure of the spiral water plenum directly determines the efficiency, running stability, and noise level of the pump. The design method of the spiral water plenum has developed over the years, and a classic hydraulic theory design scheme system has been formed and widely adopted in the industry. However, the spiral water plenum designed using the traditional design scheme simplifies the design process, but mainly focuses on meeting the hydraulic performance, and there are some problems in process sensitivity, noise, and universality, which pose higher challenges to researchers.

[0003] After searching, new design ideas have been derived for the design of pump body spiral water plenums. For example, the patent with publication number CN103994102A discloses a spiral water plenum design method for low specific speed centrifugal pumps, which optimizes the geometric size parameters of the spiral water plenum, achieves higher hydraulic efficiency and stability, expands the operating flow range, and reduces vibration and noise. The patent with publication number CN113464495A provides a spiral water plenum for automatically balancing radial forces in a multi-stage pump and a design method thereof. By designing symmetrical spiral water plenums in the multi-stage pump, the use of symmetrically arranged partitions and diffuser pipes allows the impeller to generate counteracting radial forces, solving the vibration problem caused by radial forces in the prior art and improving the efficiency and service life of the pump. The patent with publication number CN113530887A provides a spiral water plenum structure for a centrifugal pump. By adjusting the expansion angle and the spiral line conservation coefficient, the efficiency reduction problem of the centrifugal pump in a large flow regulation range is solved, achieving higher efficiency and stability. It can be seen that in order to improve the performance of the pump body in multiple aspects, it is necessary to further optimize the traditional flow passage design, and the design of the water plenum flow passage has always been a hot issue in the industry. SUMMARY

[0004] 1. Technical problem to be solved by the application

[0005] The purpose of the present application is to provide a pipeline pump unit, a water plenum thereof, and a flow passage design method thereof. By optimizing the design of the flow passage, the performance of the pump unit is further improved, and the low-noise, high-efficiency, and universality of the pump unit are promoted.

[0006] 2. Technical solution

[0007] To achieve the above purpose, the technical solution provided by the present application is:

[0008] The application discloses a pipeline pump unit pressure water chamber flow channel design method. Cross-sectional flow area ;

[0009] Wherein: ;

[0010] D3 is an outer diameter of the impeller, mm;

[0011] ; b3 is an inlet width of the pressure water chamber flow channel, mm;

[0012] Cross-sectional flow area of the 8th section in the pressure water chamber Satisfies:

[0013]

[0014]

[0015] Wherein, V8 is an average velocity of the vortex section, m / s;

[0016] Q is the design flow, m 3 / s;

[0017] A8 is the cross-sectional flow area of the 8th section, mm 2 ;

[0018] H is a single-stage lift of the pump, m; H

[0019] C is a velocity coefficient, selected according to a Stepanov curve; g is a gravity acceleration, m / s 2 ;

[0020] Cross-sectional flow area of other sections in the pressure water chamber

[0021] Satisfies:

[0022]

[0023] Wherein, n is a section serial number, a positive integer 1-7;

[0024] A is the cross-sectional flow area of the nth section, mm A8 is the cross-sectional flow area of the 8th section, mm 0.135~0.175, 0.3~0.35, 0.425~0.475, 0.55~0.6, 0.635~0.675, 0.76~0.8, 0.885~0.925.

[0025] The application also provides a pipeline pump unit water pressure chamber with the flow channel designed by the method.

[0026] The application also provides a pipeline pump unit with the water pressure chamber.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the technical scheme provided by the application has the following beneficial effects:

[0029] (1) The flow channel design scheme of the application enlarges the gap between the impeller and the water pressure chamber by increasing the base circle design and the inlet width of the spiral water pressure chamber on the basis of the traditional design, so that the strength of the dynamic and static interference between the impeller and the water pressure chamber can be effectively reduced during the pump operation, the pressure pulsation generated at the outlet side of the impeller blade due to the dynamic and static interference during the pump operation is reduced, the flow-induced noise is reduced, and the flow loss is reduced; at the same time, the gap between the impeller and the water pressure chamber is enlarged, the allowable error is increased, and the interference problem between the flow channels of the impeller and the water pressure chamber caused by the manufacturing error can be avoided; in addition, the impeller with different widths and radii corresponding to different flow requirements can be compatible under the premise of meeting the performance, so that the product platform is standardized, and the universality of the product is improved.

[0030] (2) The flow channel design scheme of the application increases the eight cross-sectional areas of the water pressure chamber to different degrees on the basis of the traditional design, changes the flow velocity distribution in the water pressure chamber, reduces the high turbulent kinetic energy area of the fluid in the middle section of the water pressure chamber, and reduces the flow separation or vortex caused by the excessively high flow velocity, so as to reduce the hydraulic loss; after the flow velocity in the middle section is reduced, the kinetic energy of the fluid reaching the tongue is weakened, the impact force on the tongue and the flow-induced noise caused by local impact are reduced, so that the service life of the tongue is prolonged, and the hydraulic noise is reduced; the pressure gradient distribution in the water pressure chamber is adjusted, the asymmetric pressure at the outlet of the impeller is partially offset, and the radial force generated by the asymmetric pressure near the tongue of the spiral water pressure chamber is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 FIG. 1 is a structural schematic diagram of a pump unit in an embodiment;

[0032] Figure 2 FIG. 2 is a structural schematic diagram of the cross-sectional distribution of the flow channel of the water pressure chamber in the embodiment.

[0033] Figure 3 Structure diagram of the impeller in the embodiment;

[0034] Figure 4 Structure diagram of the angle distribution of each section of the flow passage of the water plenum in the embodiment;

[0035] Figure 5 Structure diagram of the position distribution of the monitoring of the pressure fluctuation value of the water plenum in the embodiment;

[0036] Figure 6 Structure diagram of the noise verification result of the monitoring point P1 in the embodiment; Figure 5

[0037] Structure diagram of the noise verification result of the monitoring point P2 in the embodiment; Figure 7 Figure 5 Structure diagram of the noise verification result of the monitoring point P3 in the embodiment;

[0038] Figure 8 Figure 5 Structure diagram of the noise verification result of the monitoring point P4 in the embodiment.

[0039] Figure 9 Structure diagram of the noise verification result of the monitoring point P4 in the embodiment. Figure 5 Explanation of the reference numerals in the schematic diagrams:

[0040] 100, pump body; 200, impeller; 300, water plenum.

[0041] DETAILED DESCRIPTION In order to further understand the present application, the application will be described in detail with reference to the accompanying drawings.

[0042] In the description of the present application, it should be noted that the terms “center”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “inner”, “outer” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms “first”, “second”, “third” are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0043] The present application will be further described below in conjunction with the embodiments.

[0044] EMBODIMENT

[0045] In conjunction with

[0046] Figures 1-4 ​​​As shown, to more fully understand the solution of this embodiment, the traditional design scheme of the spiral pressure chamber in the industry will be described first. The pump unit includes a pump body 100, within which an impeller 200 is located, forming a spiral pressure chamber 300. The key dimension of the pressure chamber 300 includes the base circle of the spiral pressure chamber 300. The inlet width of the 300mm flow channel in the pressure chamber and the cross-sectional area of ​​the flow channel In this invention, the flow area of ​​the 8th cross section is used. The size of the flow channel cross-sectional area is used to characterize the flow channel. The base circle is the circle tangent to the starting point of the spiral line of the spiral pressure chamber 300; the inlet width of the pressure chamber 300 is the width of the flow channel, i.e., the transverse dimension of the flow channel perpendicular to the flow direction. The first one in the plan view of the pressure chamber 300 The cross-sectional area of ​​the flow path; For the first The cross-sectional position angle of a section is defined. These represent the starting and ending points of the cross-sectional position angles, i.e., 0° and 360°. The cross-sectional position angle for the first cross-section is 45°, for the second cross-section it is 90°, and so on. The parameters are as follows: Figure 1 and Figure 2 As shown.

[0047] The traditional spiral pressure chamber design in the industry is mainly based on the following design scheme:

[0048] Base circle size Typically, the impeller outer diameter is 200 mm. 1.03 to 1.08 times, that is:

[0049] .

[0050] 300mm inlet width of pressure chamber In traditional design, Typically, the impeller outlet width is 200 mm. 1.6 to 2 times, that is:

[0051] .

[0052] Cross-sectional area distribution: Area of ​​section 8 Calculated using the velocity coefficient method, based on the principle of equal velocity, the cross-sectional areas are distributed proportionally according to the angle, i.e., the flow area of ​​the 8th cross-section in the 300 plan view of the spiral plenum chamber. satisfy:

[0053]

[0054]

[0055] in, The average velocity of the vortex chamber cross section is expressed in m / s.

[0056] H represents the pump's single-stage head, in meters (m).

[0057] This is the velocity coefficient, the value of which can be selected based on the Stepanov curve;

[0058] g is the acceleration due to gravity, m / s² 2 ;

[0059]

[0060] in, The serial number is a positive integer from 1 to 7;

[0061] The first one in the plan view of the pressure chamber 300 The cross-sectional area of ​​the flow path, in mm² 2 ;

[0062] For the first The cross-sectional position angle of a section is defined. Let 0° and 360° be the starting and ending points of the cross-sectional position angles. Then, the cross-sectional position angle of the first cross-section is 45°, the cross-sectional position angle of the second cross-section is 90°, and so on. Figure 1 and Figure 2 As shown.

[0063] The traditional design approach, which focuses on meeting hydraulic performance requirements, simplifies the design process. However, through long-term practice, the applicant has found that this design still results in significant drawbacks for the pump body in terms of process sensitivity, noise levels, and versatility. These are specifically manifested as follows:

[0064] First, the base circle With import width The design is sensitive to manufacturing errors. The design is too compact, resulting in a very small gap between the impeller 200 and the pressure chamber 300. If the outer diameter or outlet width of the impeller 200 is too large during casting or machining, it is very easy to cause friction between the impeller 200 and the pump body 100. Considering the amplification effect of dynamic and static interference in high-speed canned pumps, the small base circle diameter exacerbates the intensity of dynamic and static interference, resulting in a higher pressure pulsation amplitude and causing vibration and noise pollution.

[0065] Secondly, in the traditional design, the mode of "one pump and one pressure water chamber" is adopted, and the parameter ratio in the traditional design scheme limits the adaptation range, cannot cover the change demand of the outer diameter and the outlet width of the impeller 200, does not have universality, is difficult to adapt to the impellers 200 of different flow demands in the same series, leads to high development cost and long development period. Due to the dynamic pressure expansion characteristics of the fluid in the spiral flow passage, the area gradient of the first several sections is large, and flow separation zones and vortexes are easily formed in the first half of the flow passage. Due to the asymmetry of the structure, the impeller 200 is close to the partition tongue, and high pressure pulsation is easily generated, leading to large radial force, thereby causing vibration and noise, affecting the stable operation of the pump; and the partition tongue area is easy to produce vortex due to flow state mutation, leading to serious local wear.

[0066] In view of the above situation, the present application provides a new pipeline type pump unit pressure water chamber flow passage design scheme, through the coordinated adjustment of the base circle , the inlet width and the section area, the gap between the impeller 200 and the pressure water chamber 300 is expanded while meeting the hydraulic performance, the casting and machining tolerance is increased, the production process is good, the tolerance to casting or machining error is high, the risk of interference friction of the water pump caused by production process, manufacturing error and assembly deviation is greatly reduced.

[0067] Secondly, the spiral pressure water chamber pump body designed by the design method provided by the present application has larger base circle and inlet width size compared with the pump body designed by the traditional spiral pressure water chamber, and therefore has good compatibility to impellers 200 of different outer diameters and widths, has high universality, greatly reduces the types of pump bodies of series development products, and thereby reduces the development cost.

[0068] Finally, the traditional spiral pressure water chamber calculates the area of each section based on the principle of equal velocity by the velocity coefficient method, this method simplifies the design process, but does not consider the dynamic pressure expansion characteristics of the fluid in the spiral flow passage. For example, the area gradient of the first several sections is large, leading to sudden drop of flow velocity, and flow separation zones are easily formed in the first half of the flow passage. In the present application, the spiral pressure water chamber 300 is designed with large flow area, the area of each section is adjusted to different degrees, the area gradient of each section is optimized, the flow separation and impact loss are reduced, the outlet flow velocity is low, the pressure pulsation is low, the radial force is small, and the like.

[0069] It can be seen that the flow passage design scheme of the present application can systematically solve the multi-target conflict, through the coordinated adjustment of the base circle, the inlet width and the section area, low noise, high efficiency and high universality are realized at the same time, the influence of the base circle expansion on the efficiency is effectively balanced, the leakage loss is caused by the too large gap, the influence of the inlet width expansion on the flow velocity distribution, and the suppression effect of the section area gradient on the turbulence.

[0070] The design scheme of the application is described in detail as follows by taking an energy-saving shield pump as an example.

[0071] The basic parameters of the shield pump in this case are as follows:

[0072] Design flow = 2m 3 / h, design head H = 5.3m, and design rotating speed is 5300rpm. The size parameter of the existing impeller 200 is outer diameter 38.5mm, and the outlet width of the impeller 200 is 3.2mm. The water plenum 300 is designed based on the above.

[0073] The key size design formula of the spiral water plenum 300 is as follows:

[0074] S1, on the basis of the traditional water plenum design method, the base circle is redundantly designed, the gap between the impeller 200 and the water plenum 300 is expanded, the base circle position and the indication are , Figure 1 , Figure 2 , which satisfies:

[0075]

[0076] wherein, is the outer diameter of the impeller, and the unit is mm.

[0077] In this embodiment, the specific value is . In practice, 1.5, , , , , , etc. can also be used.

[0078] S2, on the basis of the traditional water plenum design method, the inlet width of the water plenum 300 is increased, the inlet width of the water plenum 300 is , Figure 1 , which satisfies:

[0079]

[0080] wherein, is the outlet width of the impeller, and the unit is mm.

[0081] In this embodiment, the coefficient is 3.75, and the calculated value is . In practice, 2.5, , , , can also be used.

[0082] ​​​S3, the flow area of the 8th section in the plan view of the spiral pressure water chamber is calculated according to the traditional calculation method, and the flow area of the 8th section is Satisfies:

[0083]

[0084]

[0085] wherein, is the average velocity of the vortex section, in m / s;

[0086] is the design flow, in m / s; 3

[0087] is the flow area of the 8th section;

[0088] H is the single-stage lift of the pump, in m;

[0089] g is the acceleration of gravity, m / s 2 ;

[0090] is the velocity coefficient, which can be selected according to the Stepanov curve.

[0091] In this embodiment, the spiral pressure water chamber adopts a rounded rectangular section, as shown in Figure 1 , according to the Stepanov curve, the value of is selected, and the calculated .

[0092] S4, the areas of other sections are calculated according to the following formula:

[0093]

[0094] wherein, is the serial number, which is a positive integer 1-7;

[0095] is the flow area of the th section in the plan view of the pressure water chamber, in mm 2 ;

[0096] is the flow area coefficient of the th section in the plan view of the pressure water chamber.

[0097] The traditional pressure water chamber design method in the industry distributes the areas of each section according to the angle proportion according to the principle of equal velocity, that is, the coefficient is:

[0098] is 0.125, is 0.25,​ 0.375 0.5 0.625 0.75 It is 0.875;

[0099] Compared to the cross-sectional area obtained by traditional methods, this invention adjusts... The numerical values ​​are optimized for the flow area of ​​other cross-sections, increasing the flow area of ​​each cross-section to varying degrees. Specifically, in this embodiment, the flow area coefficient of the pressure chamber cross-section is... The values ​​differ from those of traditional design methods as follows:

[0100] The value is between 0.135 and 0.175, and in practice, specific values ​​such as 0.135, 0.145, 0.15, 0.155, 0.16, 0.165, 0.17, and 0.175 can be used.

[0101] The value is 0.3~0.35, and in practice, specific values ​​such as 0.3, 0.32, 0.33, and 0.35 can be used.

[0102] The value is between 0.425 and 0.475, and in practice, specific values ​​such as 0.425, 0.435, 0.445, 0.455, 0.465, and 0.475 can be used.

[0103] The value is 0.55~0.6, and in practice, specific values ​​such as 0.55, 0.56, 0.58, and 0.6 can be used.

[0104] The value is 0.635~0.675, and in practice, specific values ​​such as 0.635, 0.645, 0.65, 0.655, 0.66, 0.67, and 0.675 can be used.

[0105] The value is 0.76~0.8, and in practice, specific values ​​such as 0.76, 0.78, and 0.8 can be used.

[0106] The value is 0.885~0.925, and in practice, specific values ​​such as 0.885, 0.895, 0.9, 0.915, 0.92, and 0.925 can be used.

[0107] For comparative verification, the design of pressure chamber A was based on the traditional pressure chamber design scheme in the industry, and the following was adopted. , The cross-sectional area is distributed according to the principle of equal velocity, and the area of ​​each cross-section is proportional to the angle, i.e., the coefficient. 0.125, 0.25 0.375 0.5 0.625 0.75 It is 0.875.

[0108] The design of pressure chambers B, C, and D is based on the design scheme of this invention. Pressure chamber B is selected according to the lower limit of the coefficient. , Cross-sectional area according to coefficient 0.135 0.3 0.425 0.55 0.635 0.76 The value is allocated to 0.885; the pressure chamber C is taken according to the upper limit of the coefficient. , Cross-sectional area according to coefficient 0.175 0.35 0.475 0.6 It is 0.675. 0.8 The allocation is 0.925; the pressure chamber D is taken as... , Cross-sectional area according to coefficient 0.145 0.32 0.43 0.57 0.65 0.78 It is allocated to 0.9.

[0109] Simulation comparison and verification were performed, and the noise verification results are as follows: Figure 4 As shown. Among them Figure 3 Table 1 shows the locations of pressure pulsation monitoring points P1, P2, P3, and P4. The maximum turbulent kinetic energy of the pressure chamber at the design point for schemes A, B, C, and D is shown in Table 1.

[0110] Table 1 Comparison of Maximum Turbulent Kinetic Energy for Each Scheme

[0111]

[0112] It is evident that the flow channel design scheme of the present invention has lower pressure pulsation value, smaller turbulent kinetic energy and higher process fault tolerance, which has outstanding practical significance.

[0113] The above description of the application and its embodiments is illustrative only, and not restrictive, and is only one of the embodiments of the application, and is not limited thereto. Therefore, if a person skilled in the art is inspired by it, without departing from the spirit of the application, similar structural modes and embodiments are not created by creative design, and all should belong to the protection scope of the application.

Claims

1. A method for designing the flow channel of the pressure chamber of a pipeline pump unit, characterized in that, The pump body (100) has an impeller (200) and forms a spiral pressure chamber (300). The key dimensions of the pressure chamber (300) include: the base circle D3 of the spiral pressure chamber (300), the inlet width b3 of the flow channel of the pressure chamber (300), and the third... Cross-sectional area ; in: ; The outer diameter of the impeller (200) is in mm; ; The impeller outlet width is in mm. The flow area of ​​the 8th section in the pressure chamber (300) satisfy: in, is the average velocity of the vortex chamber cross section, in m / s; For design flow rate, m 3 / s; The flow area of ​​section 8 is in mm. 2 ; H The head of the pump is in meters (m). The velocity coefficient is selected based on the Stepanov curve; g is the acceleration due to gravity, m / s² 2 ; Flow area of ​​other sections in the pressure chamber (300) satisfy: in, The section number is a positive integer from 1 to 7; For the first Cross-sectional area coefficient; where The value is between 0.135 and 0.

175. The value is 0.3~0.

35. The value is between 0.425 and 0.

475. The value is 0.55~0.

6. The value is between 0.635 and 0.

675. It is 0.76~0.

8. The value is 0.885~0.

925.

2. A pressure chamber for a pipeline pump unit, characterized in that: The flow channel of the pressure chamber (300) adopts the design method described in claim 1.

3. A pipeline pump unit, characterized in that: It has a pressure chamber (300) as described in claim 2.

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